Portable amplifier



FIG. 1 is a front view of the portable amplifier of the present invention, the rear view being a mirror image;

FIG. 2 is a left end view (relative to FIG. 1) of the portable amplifier of the present invention.

FIG. 3 is a right end view of the portable amplifier of the present invention.

FIG. 4 is a bottom view of the portable amplifier of the present invention; and,

FIG. 5 is a top view of the portable amplifier of the present invention. 

The ornamental design for a portable amplifier, as shown and described. 